Turbochargers are forced-induction devices that are utilized to increase the pressure of the intake air provided to an internal combustion engine. Exhaust gas from the engine is routed to the turbocharger to drive a turbine wheel. The torque generated by the turbine wheel drives a compressor wheel, which pressurizes intake air for supply to the engine. By pressurizing the intake air, the engine may have increased power output compared to an otherwise comparable naturally-aspirated engine.
The turbine wheel and the compressor wheel may be connected by a shaft, which is rotatably supported in a bearing housing positioned therebetween. High temperatures associated with the exhaust gas increases may increase temperature of the bearing housing and/or lubrication or cooling features associated with the bearing housing. As the temperature associated with the bearing housing increases, the lubrication or cooling features may become ineffective, components of the bearing housing may become damaged or rendered ineffective, other components associated with the turbocharger may become damaged or rendered ineffective, or a combination thereof.
To limit heat transfer from the exhaust to the bearing housing, a heat shield may be positioned between the turbine wheel and the bearing housing. The heat shield is configured as a plate- or disc-like structure, which may be subject to thermal growth primarily in the radial direction. When constrained in the radial direction, the heat shield may deflect axially. Such axial deflection of the heat shield may have undesired consequences such as creating too little clearance to the turbine wheel, which may result in collision with the turbine wheel or even undesirable aerodynamic conditions causing frictional losses or unfavorable seal pressure gradients.